FOXP3 expression accurately defines the population of intratumoral regulatory T cells that selectively accumulate in metastatic melanoma lesions

摘要: Regulatory T (T(reg)) cells are often found in human tumors; however, their functional characteristics have been difficult to evaluate due low cell numbers and the inability adequately distinguish between activated T(reg) populations. Using a novel approach, we examined intracellular cytokine production capacity of tumor-infiltrating single-cell suspensions enzymatically digested tumors differentiate from effector cells. Similar peripheral blood healthy individuals, FOXP3(+)CD4 cells, unlike FOXP3(-) were unable produce IL-2 IFN-gamma upon ex vivo stimulation, indicating that FOXP3 expression is valid biological marker for even tumor microenvironment. Accordingly, enumerated intratumoral peritumoral sections metastatic melanoma significant increase proportion compared with areas. Moreover, frequencies 3- 5-fold higher than same patients or donors, respectively. These findings demonstrate CD4 population accurately depicted by expression, they selectively accumulate tumors, frequency does not properly reflect